KYIV -- Several hundred Ukrainians have gathered outside the Interior Ministry in Kyiv to demand the resignation of Interior Minister Vitaly Zakharchenko after an opposition journalist known for her investigations into government corruption was attacked.
Tetyana Chornovol, 34, was dragged out of her car and savagely beaten near Kyiv early on December 25, just hours after an article she wrote on the assets of top government officials was published.
Chornovol, who writes for the "Ukrainska Pravda" opposition website, is a prominent activist who has given speeches at recent antigovernment protests.
The chief of Ukrainian Investigative Directorate, Mykola Chynchyn, was quoted on the Interior Ministry website
on December 27 as saying that five suspects had been taken into custody.
It was unclear whether any of the three unidentified lawmakers they had said were under questioning were among those arrested.
Protesters have condemned the attack and vowed not to leave Independence Square, where weeks-long antigovernment demonstrations continue.
"This [attack on Tetyana Chornovol] was very brutal. It was a brutal action by the people who did that. I watched on television yesterday how this all happened. It is not hooliganism, it is an attempted murder," one protester, Oleksiy, said.
WATCH: Chornovol's dashcam captured the assailants, after a long chase, eventually ramming her off the road.
The Interior Ministry initially said they believed three people were involved in the assault and announced the third of three arrests on December 26.
They added that investigators were questioning three unidentified members of parliament, although they did not say how they might be connected to the case.
Pro-EU demonstrators have been occupying central Kyiv but their numbers began falling after Russia offered Ukraine a $15 billion bailout this month.
However, the attack against Chornovol appears to have given a new impetus to protesters. One of them, Mykola vowed to continue the demonstrations into next year: "We came here to stay until the very end and we are not planning to leave. We will be celebrating the New Year here on the square."
The United States has expressed its "grave concern" over what it calls an "emerging pattern of targeted violence and intimidation" aimed at activists and journalists who have participated in or reported on the pro-EU protests in Ukraine.
In a statement, State Department spokeswoman Jen Psaki said the beating of Chornovol is "particularly disturbing."
She called on the government of Ukraine to uphold its OSCE commitments and ensure respect for human rights. She also urged Kyiv to send an "unequivocal message" that violence against government critics will not be tolerated.
Meanwhile, on December 26, ratings agency Standard & Poor's (S&P) raised its outlook for Ukraine to stable from negative.
S&P said the cash injection of $15 billion -- about 8 percent of Ukraine's predicted 2014 gross domestic product -- "should cover the government's external financing needs over the next 12 months."
S&P added that "based on our expectations of Russia's support" it no longer expected a devaluation of the Ukrainian hryvnia.
But the agency also warned that the Russian support appeared subject to good diplomatic relations between the two ex-Soviet states being maintained.
With reporting from Reuters, AFP, and Interfax